The annoyance often attributed to “gnats” is typically caused by tiny, nearly invisible biting flies, most commonly known as biting midges or no-see-ums. These insects, barely one to three millimeters in length, can easily spoil outdoor activities with their painful, irritating bites. Their small size and ability to swarm means a person often feels the bite before seeing the culprit. Understanding the behavior of these attackers and implementing targeted prevention methods can greatly reduce the number of bites.
Understanding the Biting Insects
The biting insects frequently called gnats are usually members of the family Ceratopogonidae, known as biting midges, sand gnats, or no-see-ums. These pests are distinct from non-biting insects like fungus gnats or fruit flies. Only female midges bite, as they require a blood meal for the development and production of their eggs.
Midges use specialized mouthparts with cutting teeth to puncture the skin, creating a small wound to draw blood. They are highly attracted to the carbon dioxide humans exhale, body heat, lactic acid, and body odor, which signal a potential host. Biting midges are most active during the calm, cooler hours of the day, specifically around dawn and dusk.
These insects thrive in moist environments, often found near marshy areas, water sources, and damp soil. They avoid strong winds, meaning their activity increases on cloudy, windless days. They rarely venture far from their breeding grounds, so knowing their preferred habitats and peak activity times is key to effective avoidance.
Personal Protection Strategies
Applying insect repellent to exposed skin is the most direct method for preventing bites. The most effective products contain active ingredients that interfere with the insects’ sensory receptors. Repellents containing DEET, Picaridin, or Oil of Lemon Eucalyptus (OLE) are recommended for protection against biting midges.
For long-lasting protection, look for products with 25% to 30% DEET, or about 20% Picaridin. Picaridin is often favored because it is non-greasy and does not damage plastics or synthetic fabrics. Oil of Lemon Eucalyptus (OLE), which contains the compound p-menthane 3,8-diol (PMD), is an effective alternative to DEET, though it may require more frequent reapplication.
Physical barriers provide a layer of defense in addition to topical repellents. Wearing long-sleeved shirts and long pants made of tightly woven material prevents midges from reaching the skin. Since these tiny insects can penetrate loosely woven fabric, treating clothing and gear with Permethrin increases the barrier’s effectiveness. Permethrin should be applied to clothing only, never directly to the skin, and allowed to dry completely before wearing.
Modifying Your Immediate Environment
Since biting midges require moisture to reproduce, eliminating sources of standing water is a primary control measure. Regularly empty containers such as birdbaths, planters, and clogged gutters, which harbor water. Addressing areas of poor drainage and managing overly damp soil in your yard will reduce potential breeding sites.
Airflow is a simple yet powerful deterrent because biting midges are weak fliers. Setting up fans outdoors, particularly on decks or patios, creates a breeze that makes it difficult for the insects to navigate and land. This strong air current effectively keeps a localized area clear of swarming midges.
Securing your home’s entry points is another modification, as midges are small enough to pass through standard window screening. Upgrading to a finer mesh screen (smaller than 16 mesh) can block their entry. Limiting outdoor activity during the peak biting hours of dawn and dusk, especially on calm, overcast days, reduces your overall exposure.
Treating Bites and Managing Irritation
Despite prevention efforts, bites may still occur, and immediate care minimizes discomfort and irritation. First, wash the affected area gently with warm water and mild soap. Avoid scratching the bites, as this can break the skin and increase the risk of a secondary bacterial infection.
To manage the itching and swelling that follows a bite, apply a cold compress or ice pack wrapped in a cloth for about 15 minutes. Over-the-counter topical treatments provide relief; look for anti-itch creams containing hydrocortisone or topical antihistamines. Calamine lotion is another option to soothe the irritation.
If you experience numerous bites or a severe reaction, oral antihistamines may reduce the body’s allergic response to the insect’s saliva. Most bites resolve within a few days. Seek medical attention if swelling worsens, the area becomes hot to the touch, or you develop signs of infection. A severe allergic reaction, such as hives or difficulty breathing, requires immediate professional care.